Screening and molecular analyses for biosurfactant production by Pseudomonas aeruginosa strains from oil polluted soil

In the last years the biosurfactants drawn considerable attention especially for their convenient properties. The main goal of the present study was to analyze Pseudomonas strains with high ability to produce biosurfactants during growth on n-hexadecane and Fluka-oil, and to evaluate the cell surface hydrophobicity. Biosurfactant production was screened by determining hemolysis on blood agar, blue halo on CTAB agar and emulsification activity. For tested Pseudomonas strains the emulsification index E24 values ranged between 18-58% (n-hexadecane) and respectively 15-40% for Fluka-oil. In the same time, specific genes responsible for biosynthesis of rhamnolipids were detected for bacterial strains. The obtained results showed that Pseudomonas aeruginosa K7 strain presented the lowest hydrophobic properties of the cell surface also for n-hexadecane (19.28%) and Fluka-oil (12.05%). The highest hydrophobicity was obtained for Pseudomonas aeruginosa K2 strain: 42.11% for n-hexadecane and respectively 72.73% for Fluka-oil. However, these results demonstrate that tested bacterial strains are the valuable for the future biotechnological applications.